Semiconductor device having a memory and manufacturing method thereof

Abstract

The performances of a semiconductor device of a memory element are improved. Over a semiconductor substrate, a gate electrode for memory element is formed via overall insulation film of gate insulation film for memory element. The overall insulation film has first insulation film, second insulation film over first insulation film, third insulation film over second insulation film, fourth insulation film over third insulation film, and fifth insulation film over fourth insulation film. The second insulation film is an insulation film having charge accumulation function. Each band gap of first insulation film and third insulation film is larger than the band gap of second insulation film. The third insulation film is polycrystal film including high dielectric constant material containing metallic element and oxygen. Fifth insulation film is polycrystal film including the same material as that for third insulation film. Fourth insulation film includes different material from that for third insulation film.

What is claimed is: 
     
       1. A semiconductor device, comprising:
 a semiconductor substrate; 
 a gate insulation film for a memory element formed over the semiconductor substrate; and 
 a gate electrode for the memory element formed over the gate insulation film, 
 wherein the gate insulation film has a first insulation film, a second insulation film over the first insulation film, a third insulation film over the second insulation film, a fourth insulation film over the third insulation film, and a fifth insulation film over the fourth insulation film, 
 wherein the second insulation film is an insulation film having a charge accumulation function, 
 wherein respective band gaps of the first insulation film and the third insulation film are larger than the band gap of the second insulation film, 
 wherein the third insulation film is a polycrystal film formed of a high dielectric constant material containing a metallic element and oxygen, 
 wherein the fifth insulation film is a polycrystal film formed of the same material as that for the third insulation film, and 
 wherein the fourth insulation film is formed of a different material from that for the third insulation film. 
 
     
     
       2. The semiconductor device according to  claim 1 ,
 wherein the third insulation film is an aluminum oxide film, an aluminum oxynitride film, or an aluminum silicate film. 
 
     
     
       3. The semiconductor device according to  claim 1 ,
 wherein the third insulation film is an aluminum oxide film. 
 
     
     
       4. The semiconductor device according to  claim 1 ,
 wherein the second insulation film is formed of a high dielectric constant material containing hafnium and oxygen. 
 
     
     
       5. The semiconductor device according to  claim 1 ,
 wherein the second insulation film is a hafnium oxide film or a hafnium silicate film. 
 
     
     
       6. The semiconductor device according to  claim 1 ,
 wherein the first insulation film is a silicon oxide film or a silicon oxynitride film. 
 
     
     
       7. The semiconductor device according to  claim 1 ,
 wherein a plurality of first crystal grains forming the third insulation film, and a plurality of second crystal grains forming the fifth insulation film are separated by the fourth insulation film. 
 
     
     
       8. The semiconductor device according to  claim 7 ,
 wherein the first crystal grains forming the third insulation film include third crystal grains adjacent to the second insulation film and the fourth insulation film, and 
 wherein the second crystal grains forming the fifth insulation film include fourth crystal grains adjacent to the fourth insulation film and the gate electrode. 
 
     
     
       9. The semiconductor device according to  claim 1 ,
 wherein the fourth insulation film is a polycrystal film formed of a high dielectric constant material. 
 
     
     
       10. The semiconductor device according to  claim 1 ,
 wherein the fourth insulation film is a metal oxide film, a metal silicate film, or a metal oxynitride film. 
 
     
     
       11. The semiconductor device according to  claim 1 ,
 wherein the fourth insulation film is an amorphous film. 
 
     
     
       12. The semiconductor device according to  claim 1 ,
 wherein the fourth insulation film is a silicon oxide film, a silicon oxynitride film, or a silicon nitride film. 
 
     
     
       13. The semiconductor device according to  claim 1 ,
 wherein the fourth insulation film is thinner than each of the third insulation film and the fifth insulation film. 
 
     
     
       14. The semiconductor device according to  claim 13 ,
 wherein a thickness of the fourth insulation film is 1 nm or more. 
 
     
     
       15. The semiconductor device according to  claim 14 ,
 wherein each thickness of the third insulation film and the fifth insulation film is 2 nm Or more. 
 
     
     
       16. The semiconductor device according to  claim 13 ,
 wherein the third insulation film is thinner than the fifth insulation film. 
 
     
     
       17. The semiconductor device according to  claim 13 ,
 wherein the fifth insulation film is thinner than the third insulation film. 
 
     
     
       18. A semiconductor device, comprising:
 a semiconductor substrate; 
 a gate insulation film for a memory element formed over the semiconductor substrate; and 
 a gate electrode for the memory element formed over the gate insulation film, 
 wherein the gate insulation film has a first insulation film, a second insulation film over the first insulation film, a third insulation film over the second insulation film, a fourth insulation film over the third insulation film, and a fifth insulation film over the fourth insulation film, 
 wherein the second insulation film is an insulation film having a charge accumulation function, 
 wherein respective band gaps of the first insulation film and the third insulation film are larger than the band gap of the second insulation film, 
 wherein the third insulation film is a polycrystal film formed of a high dielectric constant material containing a metallic element and oxygen, 
 wherein the fifth insulation film is a polycrystal film formed of the same material as that for the third insulation film, and 
 wherein the fourth insulation film is a polycrystal film having a different crystal structure from that of the third insulation film.